Britney Spears' little sister Jamie Lynn fell pregnant aged 16 because she was "really scared" to discuss birth control with her doctor.

The actress/singer was too nervous to ask for contraception advice but admits she was stunned to learn she was expecting her first child with then-boyfriend Casey Aldridge.

She tells Glamour magazine, "I had been on a Nickelodeon show, Zoey 101, and after we wrapped shooting, I just wanted to go home to Louisiana and finish high school, be a cheerleader, all that. Then I found out I was pregnant. I was 16. I'd had one boyfriend. It doesn't make it perfect or all right. But I was judged for something that probably most everyone does... I was like every other teenager, except I had this last name...

"I believe in safety and birth control as prevention. But like many young girls... I was really scared to go to the doctor. And I was on a Nickelodeon show, and it (felt) especially embarrassing to ask someone to put me on birth control. I didn't want to ask my doctor."

Spears, now a single mum at 20, plans to teach her three-year-old daughter Maddie all about safe sex when she is a teenager to help her make "smart choices".

She adds, "It'd be dumb to sit here and say that Maddie isn't going to like a boy one day and she isn't going to have a boyfriend. I'll just have to handle that the best way that I can. Both her daddy and me will caution her (about having sex), and I would hope that she would not want to do that at all, but I have to make sure that I'm realistic too. I've got to figure out a way to communicate to her to make smart choices and make the best decisions she can."